| Scallops have a high nutritional and medicinal value,because of its very richnutrients and physiologically active ingredients, and it is a kind of marine food with threefunctions that are as medicine, food, and nourishing. With high protein and moisturecontent, the quality of scallop is easily changed during storage. Now, with the rapiddevelopment of aquaculture industry about scallops in China, fresh scallops are mainlyprocessed into quick-frozen products and instant food, however, the situation of laggingscallops preservation technology has greatly limited the sale and development of freshscallops industry. To address scallops perishing and food safety issues caused by abusingchemical preservative, the paper took bay scallops as the main raw material, developed anew type of biological preservative compound, analyzed scallops’ quality changes effectedby the biological preservative during storage, verified its positive effect in the preservationof scallops, and established a dynamic model and shelf-life model about scallops’ qualitychanges based on the effect of temperature on the scallop storage, as a result of providingimportant theoretical and technical support for industrial production and storage.The main contents and conclusions are as follows:1. The study about the effect of biological preservative on the scallop preservative. TakingpH, total number of colonies, TVB-N and sensory score as the index, the fivebiological preservative and concentration were screened through the single factorexperiment, and propolis solution, polyphenols and carboxymethyl chitosan wererelatively better for scallops preservation. Ultimately adopt0.1%to0.2%ofpolyphenols,1.0%to2.0%of carboxymethyl chitosan,0.3%to0.9%of propolissolution three kinds of biological preservative to take orthogonal test, and determinedthe best ratio of new composite preservative that was0.2%of polyphenols,1.5%ofcarboxymethyl chitosan and0.3%of propolis solution by orthogonal experiment. Theresults showed that: the complex biological preservative can effectively inhibit theincrease in the total number of colonies and scallops TVB-N content, maintain goodsensory quality, and make the shelf life of scallops in0temperature longthen7to8days from4to5days, extending from0.6to0.75times.2. The fresh-keeping research of composite biological preservative of scallop underdifferent temperature conditions.Treated the scallops with compound preservativecombined with different storage temperatures, measured the freshness indicators suchas ATP enzyme activity, K value, thiobarbituric acid (TBA), volatile basic nitrogen(TVB-N), biogenic amines, trimethylamine (TMA), and the total number of coloniesand evaluated the freshness during storage. The results showed that: the lower thetemperature was, the longer the scallops with compound preservative treatmentmaintained freshness. Each shelf life of scallops with complex biological preservativetreatment at0,-1.2,-5,-20temperature conditions was extended by2to3days,4to5days,6to8days,3to4months. The experimental results showed that the compoundinhibit the biological preservative effect of enzymes and microorganisms multiplying,delayed the process of scallops corruption, and effectively extended the shelf life of scallops.3. Exploring of ATP degradation Ways in Scallops. ATP and related compounds related to the type and content of species and the growth environment for Scallops, ATP degradation pathway is more complex of Shellfish.When AMP degradation AMP→IMP→HxR→Hx, AMP→AdR→Ad, AMP→AdR→HxR three pathway may coexist. K values measured results showed that:experiment detected IMP, HxR and Hx, not detected AdR and Ad of scallops during storage. The experiments consider that:the degradation pathway of ATP was ATP→ADP→AMP→IMP→HxR→Hx.4. Study on determination method of changes of biogenic amines in Scallops during storage.With the scallop in the bay as the research object, We used pre-column derivatization HPLC to effectively isolate tyramine, putrescine, cadaverine, histamine, tryptamine, spermine, spermidine seven kinds of biogenic amines in20minutes and analyze the changes in the types and levels of biogenic amines scallops at different storage temperature and storage time. The results show that the effection of the storage temperature on the content of difference about putrescine, spermine or spermidine, cadaverine in the scallop were significant (P<0.05), and the higher the temperature is, the faster the biogenic amines are produced.Therefore,the low temperature is an effective measure to control the scallop biogenic amines.5. The shelf-life prediction model establishment and evaluation of scallops. At10,5,0and-1.2temperature conditions, the correlation about chemical, microbiological nd sensory indicators during scallops storage were analyzed and selecting the TVB-N, the total number of colonies and K value as the key factor instructions, Arrhenius equation and a chemical kinetic equation correlation coefficient were both higher than0.9, with a high fitting accuracy.The dynamic model of TVB-N, the total number of colonies, K values obtained shelf-life prediction model of scallop are as follows:The activation energy of the reaction respectively was63.75kJ/mol,42.84kJ/mol and42.41kJ/mol. and proven the relative error between the predicted shelf life and the values measured actually is less than10%. Therefore, according the variation of TVB-N, the total number of colonies and K value at different temperature conditions during scallops storage, predicted the remaining shelf life, as a result of making theoretical foundation for the research about scallops storage shelf life and its quality and safety. |
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